Production of tin oxid and zinc oxid



D. DE ROS.

PRODUCTION OF TIN oxm AND zmc OXID.

A'PPLlCATION FILED OCT 30, I919.

1,372,407. Patented Mar. 22,1921.

ZSHEETSSHEET l.

D. DE ROS.

PRODUCTION OF TIN OXID AND ZINC OXID.

APPLICATION FILED ocr 30.1919.

1,372,407, Patented Mar. 22,1921.

2 SHEETSSHEET 2.

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PATENT OFFICE.

DUDLEY DE ROS, OF GBEENHITHE, ENGLAND.

PRODUCTION OF TIN OXID AND ZINC OXID.

To all whomit may concern:

Be it known that I, DUDLEY on Ros, a subject of the King of Great Britain, residing at Black Duck Wharf, Greenhithe, in the county of Kent, England, have invented.

certain new and useful Improvements in the Production of Tin Oxid and Zinc Oxid, of i which the following is a specification.

This invention comprises improvements in and relatin to the production of tin oxid and zinc oxi and relates to .processes in which tin or zinc,.or a material containin either of these metals, is heated or ignited by means of, for example,an oil fuel burner, and upon the attainment of a sufficiently high temperature in the mass, air or oxygen or oxidizing gas is blown into or applied to the molten mass with the result that e'xothermic action is set up and an emission of tin oxid or zinc oxid, as the case may be, takes place. I

Important objects of this invention are to effect a more perfect and economical oxidation of the metal, to reduce the working ex-- penses, to recover the metal values more exhaustively and to lengthen the life of the plant and render it less liable to injury by the intensive heating and working to which it is subjected.

More specifically the inventionhas for its object to utilize a combination or primary and secondary or high pressure and low pressure blasts in performing the exothermic reaction, the primary blast being applied to the molten mass through a submerged nozzle and the secondary blast being introduced above the surface of the mass. The function of the high pressure blast is to set up and maintain the exothermic-reaction and the low pressure blast, while effecting an economy inpower owing to its use necessitating less call upon the high pressure blast, exercises important functions in up in the body same are given by way the chamber a may Specification of Letters Patent. Patented Man. 22, 1921. Application filed October 30, 1919. Serial No. 334,423.

which by reason of an exothermic action set produces a certain amount of oxid but maintains the bath at such a high temperature that upon a low pressure blast being introduced in the region ofbut above the surface of the bath, the scull (mainly consisting of stannous oxid and stannous stannate- Sn O is oxidized to stannic oxid and large volumes of additional stannic'oxid are given off from the boiling or partly boiling bath. Nevertheless, the low pressure blast per- ,forms its advantageous function of keeping the heat withinsuch limits as will prevent overheating.

A further specific object of ,the invention is to adapt a converter ty e of furnace for the production of the oxid" in the manner aforesaid, thefurnace or, chamber being capable of tilting or rocking so as to cause the molten contents to submerge the primary or high pressure blast nozzle while leaving the secondary nozzle free to deliver a blast above the surface of the molten mass. Such an apparatus lends itself wellto the performance of subsidiary operations, as will be hereinafter explained.

Yet another object is to provide a furnace of this kind with a blast box and clearing rod device for the maintenance of full nozzle aperture, by clearing away any scull collecting 'overand obstructing the said aperture.

In order that the invention may be readily understood, suitable embodiments of the of example in the accompanying drawmgs in which 2-- Figure 1 is a sectional elevation of one con struction 'ofapparatus according to this invention. '1

Fig. 2 is a similar view of another construction and Fi 3 is a vertical section on the line III-III of Fig. 2. I

Fig. 4 is a longitudinal section of another modification. it

In the'construction of apparatus for carr'ying out these improvements, as shown in Fig. 1, there may be an elongated cylindrical or other suitably shapedl chamber a mounted. on trunnions 12 arranged transversely of the longitudinal axis and about half-way along the same. The ends a of be coned or otherwise suitably reduced and one end may be plugged at a, the plug a being fitted with of the metallic bath not only a twyer or duct e for the introduction of the high pressure blast from a box e fitted with a gland or stufling box fe and push rod e The supply connection for the box e is indicated by dotted circles at 6 The opposite end of the furnace at which is left open as at a, and serves for the introduction of the tin or the like and the flame of an oil flame burner c, where such as used, and, in any case, for the introduction of the low pressure blast or current d. In the roof or top of the chamber a is an opening which may be surrounded by a short uptake f, and this serves for drawing off the tin or zinc oxid, through a cowl and pipe 7'. A vertical branch f of the pipe may be fitted with a. damper and be adapted for drawing ofi' smoke, gases and fumes at starting up of the furnace. The chamber a is suitably lined with refractory mate'rial'in accordance with the usual practice.

At the commencement of an operation, the

' charge chamber a is heated as a preliminar step, to a temperature of, say, about 900 C., in the case of tin. For this heating, the oil flame burner a may be employed such burner that its orifice is right opposite the open'end a of the chamber a when the latter is in the horizontal position which it assumes at the commencement of a run. This preliminary heatingmay be car ried out by a suitable oil burner 1n the course posite the low of about half an hour. When the desired temperature is reached,-the chamber a is tilted, as shown in chain lines, so as to raise the open end a and depress the plugged end (F. This tilting carries the open end a oppressure blast nozzle dwhi e the high pressure blast nozzle e is appreciably submerged by the molten bath. The high pressure blast at e is turned on just prior to thetilting but not necessarily the low pressure blast at d, and owing. to the well known exothermic reaction, the temperature rapidly'rises to, say, 1500 to 1700 degrees centigrade, oxid being formed and drawn ofi. This temperature being reached, the low-pressure blast is turned on at d, being delivered above the surface of the molten bath, and while keping down the temperature and preventing it from becoming excessive, this air or oxygen in turn becomes heated and forms additional oxid from the metal in the furnace and converts the scull into stannic oxid, as will be readily understood. The level of the bath is maintained constant by the introduction, from time to time, of fresh quantities of material, and these are pushed down when necessary into the molten contents. The metal is conveniently mtroducedthrough the open end a. There should preferably be a predetermined relation between the volume of high pressure an: and the quantity of 'metal to be treated in a given time, and this being mainunplugged is tained for the attainment of a suitable temperature, the low pressure air may be regulated to suit the instant conditions in the interior of the chamber.

If scull should form at any time and tend to choke the duct or nozzle '6, the push rod (2 may be operated to clear the duct of the obstruction.

According to a modification, and as shown in Figs. 2 and 3, the elongated chamber a is formed deepest with a curved depression a at the middle. The exterior has a transversely rounded bottom a, the chamber a being suitably supported upon wheels 01- rollers g on two or more longitudinally arrangedand parallel shafts g which form a sort of cradle support for the chamber a and permit it to be rocked from one side to the other as hereinafter explained. The rounded bottom may be fitted with bands or tracks t for the wheels 9' to bear upon. The side or sides a? a of the chamber a is or are perforated and plugged, the plug or plugs 72- receiving high pressure blast fittings e as in the previously described construction. These blast nozzles 6 come opposite the greatest depth of the depression a, and are at a suitable distance above the bottom. One end of the chamber has an opening for the introduction of the burner c and the other end of the chamber has an opening for the introduction of the low pressure blast at cl. The burner c and pipe or nozzle d may be connected with their source of suppl in any suitable manner which will allow them to move with the furnace when the latter is rocked. The uptake opening or openings f is or are in the top a of the chamber as before, but the burner c is situated at the end remote from the uptake. It is preferred to arrange the burner 0 near the top and to su port a sloping deflector or tile a beneath 1t, the bottom edge of the tile lying beneath an arch or bafiie a arrangement it is possible to feed in in ots beneath the tile as indicated by dotted lines at a The deflected flame, gases and air form, as it were, a sort of screen in front of the opening through which the ingot enters, somewhat as indicated b the sloping chain lines and prevents exit 0 tin oxid, flame and vapors. With this construction, the chamber is in the position shown at the start'and after the preliminary heatin it is rocked to one side or the other in or er that one or other of the high pressure blast nozzles It shall be submer ed. The low pressure blast d is introduced through its respective end when the proper moment arrives. Now, in order that all the wear and tear shall not take place on one side only of the chamber, the latter ma be rocked, after a suitable period of wor ing, so that the nozzle which has been submerged on one side may be raised above the liquid level, and the pre- By this construction and nozzle may increased to prevent undue lowering 0 'keeps the temperature viously raised nozzle may be, in turn, submerged. Naturally, it is not only the nozzles which are under consideration but the walls of the chamber, this rocking proceeding enabling the wear or deterioration of. the lining of the chamber to be equalized on the two sides, as will be readily understood. The nozzles it may be fitted wlth push rods as in the case of the nozzle 6 Fig. 1.

In the modification illustrated in Fig. 4, which is similar in most respects tothe construction illustrated in Figs. 2 and 3, the separate low pressure blast nozzle is dis-' pensed with and the opening at that end is closed by a plug v1 which may be removable. With this arrangement, the use of the burner nozzle 0 is continued for the introduction of the low pressure blast, a small quantity of oil being permitted to pass into the furnace with such blast from say, the same supply as the burner. The oil ignitesas soon as it enters the chamber, and the combustion imparts a certain amount of heat to the air and nicety, for the .proportion of air through: the

be increased to prevent overheating and the proportion of oil mag be the temperature. This construction and modeof working are productive of a very white oxid of great purity.

" owing If desired, the secondary blast may have a pressure of, say, .15 to 0.5 pounds per square inch and the primary or high pressure blast may have a pressure of, say, 4 to 5 pounds per square inch. In some cases, however, .both blast nozzles may be supplied from the same source and the secondary blast may be adjusted to such proportions as are deemed to be suitable for the instant conditions in the furnace.

In the course of a run, the metal'is introduced from time to time, as-aforesaid, and is pushed down, if necessary, into the bath. During the run, a certain amount of scull is formed consisting of a mixture ofstannous oxid, stannous stannate a1 0, and metallictin. Now owing to the bath being maintained at a high temperature and to the introduction of the secondary blast, the low oxidsare converted into stannic oxid which is carried away by the fan or other suction means to the condenser.

In regard to all that has been said concerning the oxidation of tin, the same may be generally applicable for the oxidation of zinc with little variation as regardspractical procedure and with no departure from the rinciples forming the basis of the present invention.

I claim 1 1. A process for the production of metal oxids by applying an oxidizing blast to a molten mass and utilizing the heat from the up. Therefore, it is possible to adust the temperature to a i of metal oxid by the the surface of the molten contents,

I through an aperture exothermic reaction, which comprises introducing a blast of predetermined proportions through a submerged nozzle, and introducing a secondary blast adjusted to suit instant conditions above the surface of the mass.

2. The process for the production of metal oxids by applying an oxidizing blast to a conditions by a blast continued through said burner. i

4. A .furnace or hearth for the production of metal oxid by the process described, comprising a chamber tiltably mounted on its support and provlded with an aperture for the introduction of flame or heat, a primary blast connection on said furnace, said connection being arranged so that it is submersible upon tilting the chamber, and secondary blastmeans adapted for delivering a secondary blast into the tilted chamber above the surface of the molten contents, substantially as set forth.

'5. A furnace or hearth for the production process described, comprising a chamber adapted to tilt laterally on its support and provided with an Vapor: ture for the introduction of flame or heat, a blast connection at each side of said chamber so disposed that one connection or the other is submersible by the tilting of the chamber toward one side or the other, and means adapted for introducing blast into the upper part of said chamber and above substantially as set forth.

6. A furnace or hearth for the production.

of metal oxid by the process described, com- 11 prisin a chamber supported so as to be revolu le about a longitudinal axis and provided with an aperture for the introduction of flame or heat, a blast connection at each side of said chamber so disposed that one connection or the other is submersible by a partial revolution of said chamber, and a secondary blast adapted to deliver blast above the surface 'of the molten contentsabout on the said axis,

forth.

7 A furnace or hearth for the production of metal oxid by the process described, comprising a chamber adapted to t1lt from side substantially as set formed in an end wall to side about a longitudinal axis and formed in one end wall with an aperture about on the said axis, an atmospheric burner arranged opposite said aperture, and a blast connection at each side ,of said chamber so disposed that one connection or the other 1s submersible by tilting the furnace to one side or the other, the said aperture being adapted to leave a clear opening for the delivery from the burner at any working angle of tilt, substantially as set forth.

8. furnace or hearth.for the production of metal oxid bgethe process described,

troducjng blast in the comprising a cham r adapted to tilt, a blast nozzle connected with said chamber and so disposed as to be submersible-by the surface of the molten contents, substantially; as set forth. A

9. A furnace or hearth for the production of metal oxid by the process described, comprising a chamber adapted to tilt, a blast nozzle connected with said chamber and so disposed 'asto .be submersible by the tilting of said chamber, means for introducing a secondary blast into said chamber above the surface of the molten contents, a, deflector arranged in an aperture in a wall of said chamber and dividing said aperture into a feed inlet passage and a flame and gas inlet passage, and abaflle arranged forwardly of said deflector and adapted to cooperate with said deflector to direct a fluid screen across iaidhfeed inlet passage, substantially as set ort DUDLEY on ROS. 

